A novel Fe/HNT visible light-driven heterogeneous photocatalyst: Development as a semiconductor and photocatalytic application

Fe/HNT (Iron/Halloysite-nanotube) heterogeneous semiconductor catalysts operating effectively under visible light were developed by using FeCl₃, FeSO₄ and Fe(OH)₃ sludge precipitated after electro-Fenton process and named as Fe/HNT-I, Fe/HNT-II and Fe/HNT-III, respectively. Chemical configuration and particle morphology of the catalysts were characterized with XRD, SEM-EDS and UV–vis DRS. Effect of the developed Fe/HNT photocatalysts was investigated for the degradation of Reactive Orange 16 (RO16) textile dye under visible light. The photocatalytic decolorization of RO16 was 95.6%, 99.3% and 96.6%, respectively. It was found that the photocatalytic performance of Fe/HNT-III catalyst under visible light was effective compared to Fe/HNT-I and Fe/HNT-II. The iron ratio in the catalyst's structure (Fe:HNT ratio 0.25, 0.5 and 0.75 (w/w)) and pH value (4, 7 and 9) in production phase were also changed to investigate the photocatalytic effect of Fe/HNT-III. An Fe:HNT ratio of 0.25 and a pH of 4 were determined as the optimum conditions for catalyst production. Optimum H₂O₂ dosage value was also investigated for photocatalytic oxidation process and determined to be 10 ​mM. Finally, the optimum conditions were further used for the degradation of Terbinafine hydrochloride (TerHCl) active drug and the treatment of wastewater from the textile and pharmaceutical industries.